Due to changes made between 2.2.2 and 2.3, there is no way to have a 2.2.2 Oracle Endeca Server as a datasource for 2.3 Studio. In 2.3 we introduced a data store webservice to help manage different datasources. This required a change in how Studio queries the dgraph, as it now includes the Data Store in the query, and there is no way to have the 2.2.2 handle this new webservice request.